Immunoediting and persistence of antigen-specific immunity in patients who have previously been vaccinated with NY-ESO-1 protein formulated in ISCOMATRIX™.

BACKGROUND: NY-ESO-1 protein formulated in ISCOMATRIX™ results in CD4+, CD8+ T cell and antibody-mediated immunity. We evaluated persistence of immunity, relapse-free survival and tumour antigen expression upon relapse in patients vaccinated in an earlier trial. METHODS: Immunity was measured in 28 patients with resected NY-ESO-1-expressing tumours (melanoma 25, breast 3) 252-1,155 days (median = 681) after vaccination. In the earlier vaccination, trial patients received NY-ESO-1 with ISCOMATRIX™ adjuvant at three protein doses 10 µg, 30 µg or 100 µg (n = 14); 100 µg NY-ESO-1 protein (n = 8) or placebo (n = 6), together with 1 µg of intradermal (ID) NY-ESO-1 protein twice for DTH skin testing. Immune responses assessed in the current study included antibody titres, circulating NY-ESO-1-specific T cells and DTH reactivity 2 days after DTH skin testing with NY-ESO-1 protein (1 µg) or peptides (10 µg). Relapse-free survival was determined for 42 melanoma patients. On relapse NY-ESO-1 and HLA, class I was assessed by immunohistochemistry in 17. RESULTS: Persisting anti-NY-ESO-1 immunity was detected in 10/14 recipients who had previously received vaccine with ISCOMATRIX™ adjuvant. In contrast, immunity only persisted in 3/14 who received 100 µg un-adjuvanted NY-ESO-1 protein (3/8) or 2 µg DTH protein (0/6) P = 0.02. Hence, persisting NY-ESO-1 immunity was associated with prior adjuvant. Tumour NY-ESO-1 or HLA class I was downregulated in participants who relapsed suggesting immunoediting had occurred. CONCLUSION: Immunoediting suggests that a signal of anti-tumour activity was observed in high-risk resected melanoma patients vaccinated with NY-ESO-1/ISCOMATRIX™. This was associated with measurable persisting immunity in the majority of vaccinated subjects tested. A prospective randomised trial has been undertaken to confirm these results.

Melan-A-specific cytotoxic T cells are associated with tumor regression and autoimmunity following treatment with anti-CTLA-4.

PURPOSE: Ipilimumab is a monoclonal antibody that blocks the immune-inhibitory interaction between CTL antigen 4 (CTLA-4) and its ligands on T cells. Clinical trials in cancer patients with ipilimumab have shown promising antitumor activity, particularly in patients with advanced melanoma. Often, tumor regressions in these patients are correlated with immune-related side effects such as dermatitis, enterocolitis, and hypophysitis. Although these reactions are believed to be immune-mediated, the antigenic targets for the cellular or humoral immune response are not known. EXPERIMENTAL DESIGN: We enrolled patients with advanced melanoma in a phase II study with ipilimumab. One of these patients experienced a complete remission of his tumor. The specificity and functional properties of CD8-positive T cells in his peripheral blood, in regressing tumor tissue, and at the site of an immune-mediated skin rash were investigated. RESULTS: Regressing tumor tissue was infiltrated with CD8-positive T cells, a high proportion of which were specific for Melan-A. The skin rash was similarly infiltrated with Melan-A-specific CD8-positive T cells, and a dramatic (>30-fold) increase in Melan-A-specific CD8-positive T cells was apparent in peripheral blood. These cells had an effector phenotype and lysed Melan-A-expressing tumor cells. CONCLUSIONS: Our results show that Melan-A may be a major target for both the autoimmune and antitumor reactions in patients treated with anti-CTLA-4, and describe for the first time the antigen specificity of CD8-positive T cells that mediate tumor rejection in a patient undergoing treatment with an anti-CTLA-4 antibody. These findings may allow a better integration of ipilimumab into other forms of immunotherapy.

Regulatory T-cell-mediated attenuation of T-cell responses to the NY-ESO-1 ISCOMATRIX vaccine in patients with advanced malignant melanoma.

PURPOSE: NY-ESO-1 is a highly immunogenic antigen expressed in a variety of malignancies, making it an excellent target for cancer vaccination. We recently developed a vaccine consisting of full-length recombinant NY-ESO-1 protein formulated with ISCOMATRIX adjuvant, which generated strong humoral and T-cell-mediated immune responses and seemed to reduce the risk of disease relapse in patients with fully resected melanoma. This study examines the clinical and immunologic efficacy of the same vaccine in patients with advanced metastatic melanoma. EXPERIMENTAL DESIGN: Delayed-type hypersensitivity responses, circulating NY-ESO-1-specific CD4(+) and CD8(+) T cells, and proportions of regulatory T cells (Treg) were assessed in patients. RESULTS: In contrast to patients with minimal residual disease, advanced melanoma patients showed no clinical responses to vaccination. Although strong antibody responses were mounted, the generation of delayed-type hypersensitivity responses was significantly impaired. The proportion of patients with circulating NY-ESO-1-specific CD4(+) T cells was also reduced, and although many patients had CD8(+) T cells specific to a broad range of NY-ESO-1 epitopes, the majority of these responses were preexisting. Tregs were enumerated in the blood by flow cytometric detection of cells with a CD4(+)CD25(+)FoxP3(+) and CD4(+)CD25(+)CD127(-) phenotype. Patients with advanced melanoma had a significantly higher proportion of circulating Treg compared with those with minimal residual disease. CONCLUSIONS: Our results point to a tumor-induced systemic immune suppression, showing a clear association between the stage of melanoma progression, the number of Treg in the blood, and the clinical and immunologic efficacy of the NY-ESO-1 ISCOMATRIX cancer vaccine.

An open-label, two-arm, phase I trial of recombinant human interleukin-21 in patients with metastatic melanoma.

PURPOSE: Human interleukin-21 (IL-21) is a pleiotropic class I cytokine that activates CD8(+) T cells and natural killer cells. We report a phase 1 study of recombinant human IL-21 in patients with surgically incurable metastatic melanoma. The primary objective was to investigate safety and tolerability by determining dose-limiting toxicity (DLT). The secondary objectives were to identify a dose response for various biomarkers in the peripheral blood, estimate the minimum biologically effective dose, determine the pharmacokinetics of IL-21, determine if anti-IL-21 antibodies were induced during therapy, and measure effects on tumor size according to Response Evaluation Criteria in Solid Tumors. EXPERIMENTAL DESIGN: Open-label, two-arm, dose escalation trial of IL-21 administered by i.v. bolus injection at dose levels from 1 to 100 microg/kg using two parallel treatment regimens: thrice weekly for 6 weeks (3/wk) or three cycles of daily dosing for 5 days followed by 9 days of rest (5+9). RESULTS: Twenty-nine patients entered the study. IL-21 was generally well tolerated and no DLTs were observed at the 1, 3, and 10 microg/kg dose levels. In the 3/wk regimen, DLTs were increased in alanine aminotransferase, neutropenia, and lightheadedness with fever and rigors. DLTs in the 5+9 regimen were increased in aspartate aminotransferase and alanine aminotransferase, neutropenia, fatigue, and thrombocytopenia. The maximum tolerated dose was declared to be 30 microg/kg for both regimens. Effects on biomarkers were observed at all dose levels, including increased levels of soluble CD25 and up-regulation of perforin and granzyme B mRNA in CD8(+) cells. One partial tumor response observed after treatment with IL-21 for 2 x 6 weeks (3/wk) became complete 3 months later. CONCLUSIONS: IL-21 is biologically active at all dose levels administered and is generally well tolerated, and phase 2 studies have commenced using 30 microg/kg in the 5+9 regimen.

Directions in the immune targeting of cancer: lessons learned from the cancer-testis Ag NY-ESO-1.

Since the early 1990s, numerous cancer Ag have been defined and for a handful of these there is now some clinical experience, which has made it possible to assess their value as targets for cancer immunotherapy. The cancer-testis Ag have been particularly attractive because their expression is limited to cancer and virtually no non-malignant cells apart from germ cells and trophoblast. Among these, NY-ESO-1 has been the focus of our attention. The exceptional immunogenicity of this Ag coupled with its widespread distribution among many cancer types make it a very good vaccine candidate, with the potential to be used in vaccines against many types of malignancies. This article reviews emerging knowledge about the biology of NY-ESO-1 and experience with the early clinical development of vaccines directed against NY-ESO-1. These early studies have yielded a wealth of information about the immunology of NY-ESO-1 and set the scene for future clinical strategies for immune targeting of cancer.